| Abstract
| - A knowledge of the local structure of zeolite frameworks is an important prerequisite fora detailed and quantitative understanding of e.g. catalytic processes. In the present workthe sensitivity of 1D and 2D MAS NMR experiments to the local order of framework T atomsand energy-minimization calculations for the geometrical analysis of the complete zeoliteframework structure are combined to provide a most detailed view of their structuralproperties. Correlations of the chemical shifts, δ(29Si), with the mean distance between Siand its neighboring Si T atoms, d̄(Si−Si), are presented for the three materials MFI, MEL,and MTT. Excellent agreement between experimental and computational results wasobtained. In the case of MFI, this most complicated structure was used to demonstrate theviability of the method. The MTT and MEL systems showed that it is possible to deduce theunique assignment of the NMR spectra from energy-minimized structures when it is notpossible using the available structural data from X-ray structure analysis. Taken together,all three investigations also demonstrate that improved structural data are obtained fromlattice energy minimizations compared to those from Rietveld analysis as long as the topologyof the framework is known.
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